The present invention relates generally to a method and process for removing certain metallic ions from aqueous solutions, and more specifically to a process for the removal of such metals as copper, chromium, zinc, cadmium, nickel, platinum, antimony, iron, manganese, aluminum, thorium, tin, mercury, vanadium, rhodium and silver from aqueous solutions containing modest quantities or concentrations of these metals. Such aqueous solutions are frequently encountered in chemical processing operations, such as in plating baths, etching baths and the like, and because of disposal problems, the various aqueous solutions must be treated for removal of these metals prior to discharge into normal industrial sewage systems or the like. Also, in certain cases, the metal may have significant intrinsic value, and such materials are recovered primarily for their value.
Because of certain characteristics, a number of metals are deemed a highly undesirable element to have present in solutions destined for sewage systems. Most such systems function in a form where the presence of even minute quantities of dissolved heavy metals can disrupt the effective utilization of the sewage treatment facility. Copper is recognized as being particularly bad. This problem, as well as certain other problems are also encountered in connection with aqueous solutions containing cadmium, chromium, zinc, nickel, tin or lead. The present invention provides a procedure wherein a substantial number of metals may be effectively removed from aqueous solutions prior to their being discharged into treatment facilities. This process has application to other industries such as precious metal plating and recovery, silver recovery from photographic developer solutions and the like.